EP0262300 describes a process and an installation for producing a mass of chocolate, which involve the use of an extruder split into zones in which the successive steps of sterilizing and deodorising pieces of raw beans using pressurised steam, roasting the pieces of beans having after reduced them to a powder in a hammer mill connected in parallel with two zones which are separated by an element of screw with a flight of opposite hand, adding and mixing powdered sugar to the roasted bean powder, adding cocoa butter, and finally conducting the steps of mixing and extrusion.